Systems and methods for temperature control and heat extraction from waste landfills

Abstract

The field of the invention relates to systems and methods for exchanging heat from the degradation, decomposition, and chemical/biochemical transformation of municipal, industrial, and other types of waste. In one embodiment, a heat extraction system may include a closed-loop fluid circulation piping channeled throughout at least one heat extraction well oriented throughout a waste mass. The piping is fluidly coupled to a heat exchanger. A first circulation fluid is circulated through the closed-loop circulation piping into various depths of the waste mass to transfer thermal energy between said mass and said heat exchanger. In one embodiment, the transfer of thermal energy between the waste mass and the heat exchanger is used as alternative energy method and to control at least one of shear strength, compressibility, and hydraulic conductivity of the waste mass.

What is claimed is: 
     
         1 . A temperature control and heat exchange system comprising:
 a closed-loop fluid circulation pipe;   at least one heat transfer well providing a thermal encasement for the closed-loop fluid circulation pipe, the heat transfer well filled at intervals with a highly conductive granular backfill;   wherein the at least one heat transfer well is installed in a waste mass;   a heat exchanger having an inlet and outlet for a first circulation fluid and an inlet and outlet for a second circulation fluid;   a circulation pump operatively coupled to the closed-loop circulation pipe to provide fluid flow for the first circulation fluid; and   wherein the heat exchanger is fluidly coupled to the closed-loop fluid circulation pipe at the inlet and outlet for the first circulation fluid such that the first circulation fluid, when circulated through the closed-loop fluid circulation pipe via the circulation pump into the at least one heat transfer well distributed in the waste mass, transfers thermal energy between the waste mass and the second circulation fluid through the heat exchanger.   
     
     
         2 . The temperature control and heat exchange system of  claim 1 , further comprising:
 a microprocessor computer coupled to both the heat exchanger and the circulation pump, wherein the microprocessor computer is operable to control, via control signals, fluid flow of the first circulation fluid using the circulation pump and thermal energy transfer of the first circulation fluid using the heat exchanger.   
     
     
         3 . The temperature control and heat exchange system of  claim 2 , further comprising:
 a network of sensors integrated into the closed-loop fluid circulation pipe and the waste mass and electronically coupled to the computer providing control signals to the computer, wherein the network of sensors is operable to detect at least one of temperature, position, time, and flow-rate.   
     
     
         4 . The temperature control and heat exchange system of  claim 1 , wherein the at least one heat transfer well encasing the closed-loop fluid circulation pipe is installed in the waste mass either vertically, horizontally, or at an incline. 
     
     
         5 . The temperature control and heat exchange system of  claim 1 , further comprising:
 a thermostat-controlled trace heater operable to prevent freezing of the first circulation fluid.   
     
     
         6 . The temperature control and heat exchange system of  claim 1 , wherein the heat exchanger is a plate and frame heat exchanger. 
     
     
         7 . The temperature control and heat exchange system of  claim 1 , wherein the highly conductive granular backfill is dense gravel, soil, or industrial byproduct. 
     
     
         8 . The temperature control and heat exchange system of  claim 1 , wherein the closed-loop fluid circulation pipe is plastic, metal, or composite material. 
     
     
         9 . The temperature control and heat exchange system of  claim 1 , wherein the first circulation fluid is water, propylene glycol, or a water-glycol mixture. 
     
     
         10 . The temperature control and heat exchange system of  claim 1 , wherein the at least one heat transfer well is covered by an insulating seal at a ground surface. 
     
     
         11 . A process of controlling the temperature in a waste mass when the waste mass has at least a first, second, third, and fourth life cycle stage of biochemical processes using a heat exchanger, comprising:
 using the heat exchanger which is fluidly coupled with a first circulation fluid and a second circulation fluid to transfer a first level of thermal energy from the second circulation fluid to the first circulation fluid during the first life cycle stage of biochemical processes of the waste mass,   using the heat exchanger to transfer a second level of thermal energy from the first circulation fluid to the second circulation fluid during the second life cycle stage of biochemical processes of the waste mass,   using the heat exchanger to transfer a third level of thermal energy from the second circulation fluid to the first circulation fluid during the third life cycle stage of biochemical processes of the waste mass, and   using the heat exchanger to transfer a fourth level of thermal energy from the first circulation fluid to the second circulation fluid during the fourth life cycle stage of biochemical processes of the waste mass,   where the first circulation fluid circulates in a closed-loop fluid circulation pipe due to operation of a circulation pump coupled to the closed-loop circulation pipe and the closed-loop circulation pipe is encased in at least one heat transfer well which is filled at intervals with a highly conductive granular backfill.   
     
     
         12 . The process of controlling the temperature in a waste mass when the waste mass has at least a first, second, third, and fourth life cycle stage of biochemical processes using a heat exchanger of  claim 11 , wherein the transfer of the first level of thermal energy from the second circulation fluid to the first circulation fluid during the first life cycle stage of biochemical processes of the waste mass cools the waste mass. 
     
     
         13 . The process of controlling the temperature in a waste mass when the waste mass has at least a first, second, third, and fourth life cycle stage of biochemical processes using a heat exchanger of  claim 11 , wherein the transfer of the first level of thermal energy from the second circulation fluid to the first circulation fluid at the first life cycle stage of biochemical processes of the waste mass heats to the waste mass. 
     
     
         14 . A method of temperature control and heat exchange in a waste mass comprising:
 routing at least one heat transfer well in the waste mass;   channeling a closed-loop fluid circulation pipe into the at least one heat transfer well such that the at least one heat transfer well provides a thermal encasement for the closed-loop fluid circulation pipe, the at least one heat transfer well filled at intervals with a highly conductive granular backfill;   circulating a first circulation fluid in the closed-loop fluid circulation pipe using a circulation pump operatively coupled to the closed-loop circulation pipe; and   exchanging heat between the first circulation fluid and a second circulation fluid using a heat exchanger, the heat exchanger having an inlet and outlet for the first circulation fluid and being hydraulically coupled to provide fluid circulation to the closed-loop circulation pipe at the inlet and outlet for the first circulation fluid and having an inlet and outlet for the second circulation fluid.   
     
     
         15 . The method of temperature control and heat exchange in a waste mass of  claim 14 , wherein the heat exchanger and the circulation pump are coupled to a microprocessor computer operable to control, via control signals, fluid flow of the first circulation fluid using the circulation pump and thermal energy transfer of the first circulation fluid using the heat exchanger. 
     
     
         16 . The method of temperature control and heat exchange in a waste mass of  claim 14 , wherein exchanging heat between the first circulation fluid and the second circulation fluid influences at least one of shear strength, compressibility, and hydraulic conductivity of the waste mass. 
     
     
         17 . The method of temperature control and heat exchange in a waste mass of  claim 14 , wherein the first circulation fluid is water, propylene glycol, or a water-glycol mixture. 
     
     
         18 . The method of temperature control and heat exchange in a waste mass of  claim 14 , comprising:
 monitoring at least one of temperature, position, time, and flow-rate of the first circulation fluid using a network of sensors integrated into the closed-loop fluid circulation pipe and the waste mass, the network of sensors electronically coupled to the computer providing control signals to the computer.